QDoubleSpinBox Class
The QDoubleSpinBox class provides a spin box widget that takes doubles. More...
| Header: | #include <QDoubleSpinBox> |
| qmake: | QT += widgets |
| Inherits: | QAbstractSpinBox |
Properties
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Public Functions
| QString | cleanText() const |
| int | decimals() const |
| double | maximum() const |
| double | minimum() const |
| QString | prefix() const |
| void | setDecimals(int prec) |
| void | setMaximum(double max) |
| void | setMinimum(double min) |
| void | setPrefix(const QString &prefix) |
| void | setSingleStep(double val) |
| void | setStepType(QAbstractSpinBox::StepType stepType) |
| void | setSuffix(const QString &suffix) |
| double | singleStep() const |
| QAbstractSpinBox::StepType | stepType() const |
| QString | suffix() const |
| double | value() const |
Public Slots
| void | setValue(double val) |
Signals
| void | valueChanged(const QString &) |
| void | valueChanged(double) |
Detailed Description
QDoubleSpinBox allows the user to choose a value by clicking the up and down buttons or by pressing Up or Down on the keyboard to increase or decrease the value currently displayed. The user can also type the value in manually. The spin box supports double values but can be extended to use different strings with validate(), textFromValue() and valueFromText().
Every time the value changes QDoubleSpinBox emits valueChanged() and textChanged() signals, the former providing a double and the latter a QString. The textChanged() signal provides the value with both prefix() and suffix(). The current value can be fetched with value() and set with setValue().
Note: QDoubleSpinBox will round numbers so they can be displayed with the current precision. In a QDoubleSpinBox with decimals set to 2, calling setValue(2.555) will cause value() to return 2.56.
Clicking the up and down buttons or using the keyboard accelerator's Up and Down arrows will increase or decrease the current value in steps of size singleStep(). If you want to change this behavior you can reimplement the virtual function stepBy(). The minimum and maximum value and the step size can be set using one of the constructors, and can be changed later with setMinimum(), setMaximum() and setSingleStep(). The spinbox has a default precision of 2 decimal places but this can be changed using setDecimals().
Most spin boxes are directional, but QDoubleSpinBox can also operate as a circular spin box, i.e. if the range is 0.0-99.9 and the current value is 99.9, clicking "up" will give 0 if wrapping() is set to true. Use setWrapping() if you want circular behavior.
The displayed value can be prepended and appended with arbitrary strings indicating, for example, currency or the unit of measurement. See setPrefix() and setSuffix(). The text in the spin box is retrieved with text() (which includes any prefix() and suffix()), or with cleanText() (which has no prefix(), no suffix() and no leading or trailing whitespace).
It is often desirable to give the user a special (often default) choice in addition to the range of numeric values. See setSpecialValueText() for how to do this with QDoubleSpinBox.
Note: The displayed value of the QDoubleSpinBox is limited to 18 characters in addition to eventual prefix and suffix content. This limitation is used to keep the double spin box usable even with extremely large values.
See also QSpinBox, QDateTimeEdit, QSlider, and Spin Boxes Example.
Property Documentation
cleanText : const QString
This property holds the text of the spin box excluding any prefix, suffix, or leading or trailing whitespace.
Access functions:
| QString | cleanText() const |
See also text, QDoubleSpinBox::prefix, and QDoubleSpinBox::suffix.
decimals : int
This property holds the precision of the spin box, in decimals
Sets how many decimals the spinbox will use for displaying and interpreting doubles.
Warning: The maximum value for decimals is DBL_MAX_10_EXP + DBL_DIG (ie. 323) because of the limitations of the double type.
Note: The maximum, minimum and value might change as a result of changing this property.
Access functions:
| int | decimals() const |
| void | setDecimals(int prec) |
maximum : double
This property holds the maximum value of the spin box
When setting this property the minimum is adjusted if necessary, to ensure that the range remains valid.
The default maximum value is 99.99.
Note: The maximum value will be rounded to match the decimals property.
Access functions:
| double | maximum() const |
| void | setMaximum(double max) |
See also decimals and setRange().
minimum : double
This property holds the minimum value of the spin box
When setting this property the maximum is adjusted if necessary to ensure that the range remains valid.
The default minimum value is 0.0.
Note: The minimum value will be rounded to match the decimals property.
Access functions:
| double | minimum() const |
| void | setMinimum(double min) |
See also decimals, setRange(), and specialValueText.
prefix : QString
This property holds the spin box's prefix
The prefix is prepended to the start of the displayed value. Typical use is to display a unit of measurement or a currency symbol. For example:
spinbox->setPrefix("$");
To turn off the prefix display, set this property to an empty string. The default is no prefix. The prefix is not displayed when value() == minimum() and specialValueText() is set.
If no prefix is set, prefix() returns an empty string.
Access functions:
| QString | prefix() const |
| void | setPrefix(const QString &prefix) |
See also suffix(), setSuffix(), specialValueText(), and setSpecialValueText().
singleStep : double
This property holds the step value
When the user uses the arrows to change the spin box's value the value will be incremented/decremented by the amount of the singleStep. The default value is 1.0. Setting a singleStep value of less than 0 does nothing.
Access functions:
| double | singleStep() const |
| void | setSingleStep(double val) |
stepType : StepType
This property holds the step type.
The step type can be single step or adaptive decimal step.
Access functions:
| QAbstractSpinBox::StepType | stepType() const |
| void | setStepType(QAbstractSpinBox::StepType stepType) |
suffix : QString
This property holds the suffix of the spin box
The suffix is appended to the end of the displayed value. Typical use is to display a unit of measurement or a currency symbol. For example:
spinbox->setSuffix(" km");
To turn off the suffix display, set this property to an empty string. The default is no suffix. The suffix is not displayed for the minimum() if specialValueText() is set.
If no suffix is set, suffix() returns an empty string.
Access functions:
| QString | suffix() const |
| void | setSuffix(const QString &suffix) |
See also prefix(), setPrefix(), specialValueText(), and setSpecialValueText().
value : double
This property holds the value of the spin box
setValue() will emit valueChanged() if the new value is different from the old one. The value property has a second notifier signal which includes the spin box's prefix and suffix.
Note: The value will be rounded so it can be displayed with the current setting of decimals.
Access functions:
| double | value() const |
| void | setValue(double val) |
Notifier signal:
| void | valueChanged(double) |
| void | valueChanged(const QString &) |
See also decimals.